The present invention, in some embodiments thereof, relates to medical catheter apparatus and in particular to dialysis catheters having dual or split tip.
Split-tip dialysis catheters are mostly used in current days for chronic use of exchanging blood to and from the patient and the hemodialysis machine. During an exemplary hemodialysis procedure, a multiple lumen catheter is inserted into a body and blood is withdrawn through an arterial lumen of the catheter. This blood is supplied to a hemodialysis machine which dialyzes, or cleans, the blood to remove waste and excess water. The dialyzed blood is returned to the patient through a venous lumen of the catheter. Flow in the catheter may need to be reversed from time to time so that blood will flow in opposite direction in both arterial lumen and venous lumen to as mentioned above.
Some complications may occur in split tip catheters. At first, recirculation of blood flow is a known phenomenon in which the dialyzed blood exiting a catheter's lumen is directly returned to the other lumen without efficiently affecting surroundings. Another complication of hemodialysis catheters is flow occlusion. Flow occlusion is primarily caused by blockage of the arterial lumen. Common causes of occlusion are fibrin sheath formation, thrombus formation and positional occlusion. With positional occlusion of the catheter, there can be difficulty in removing blood from the patient. For example, a tip of the catheter has, to some extent, freedom of movement inside the patient, and this can cause occlusion, as a tip of the catheter or a side hole may be sucked against a blood vessel or heart wall.
In addition, split or dual tip dialysis catheters pose a unique feature in their current design, which makes them more prone to clotting complications. The area immediately below the separation zone of the two lumens (i.e., immediately distal to the junction) is a source of problem. With current known designs, in which the two lumens are separated directly away from each other, there is a dead space with slow and turbulent flow which makes this area very likely to form a clot. Those blood clots are a major complication of split tip dialysis catheters and are associated with increased morbidity.
The following Patent documents are believed to represent the current state of the art: U.S. Pat. Nos. 5,800,414; 5,947,953; 7,108,674; 7,182,746; 7,776,005; 8,066,660; and 8,092,415.